Apolar surface area determines the efficiency of translocon-mediated membrane-protein integration into the endoplasmic reticulum

摘要

In eukaryotic cells, membrane proteins destined for the plasma membrane and many intracellular compartments are synthesized by endoplasmic reticulum (ER)-bound ribosomes-the cell's protein builders. Proteins are then integrated into the membrane of the ER in a process mediated by the Sec61 translocon complex. During the membrane-integration step, a-helical hydrophobic segments in the translocating nascent polypeptide chain exit the Sec61 translocon and become embedded in the surrounding lipid bilayer (1).